LOS ANGELES – Nonito Donaire Jr. is ready for his next and arguably biggest challenge.

The Filipino IBF Flyweight champion Donaire faces off against Moruti Mthalane of South Africa as a co-main event on November 1 featuring Julio Cesar Chavez Jr. at the Mandalay Bay Resort and Casino in Las Vegas.

Mthalane is the No. 1 contender and a mandatory challenger for Donaire.

“I’ve worked too hard to earn this title and there is no way I’m letting anyone take it away from me,” said Donaire during a press conference announcing the fight at the Hyatt Regency Hotel in Century City. “Mthalane is going back to South Africa without the only souvenir he craves most my world championship belt.”

Mthalane (22-1, 15 KOs) will make his US debut. He’s undefeated in three years winning 10-bouts eight by knockout.

“This is my first fight outside of South Africa and I intend to make the most of it,” said Mthalane, in a press statement. “I’m going to be in the middle of the ring. Donaire will not have a problem finding me. Let’s see how he handles my pressure when he does.”

Mthalane earned his first world title shot by defeating Hussein Hussein in a 12-round unanimous decision in July.

The 25-year-old Donaire (19-1 12 KO’s) known as the “Filipino Flash” has not fought since he defeated Luis Maldonado last December in Connecticut.

Fight fallouts, promotional gaffes and a lawsuit had delayed Donaire’s career, which appeared to be on the rise after his stellar knockout victory against Vic Darchinyan to capture the IBF/ IBO championship belts last year.

He signed with Top Rank in June, got married in August and is know focus on the task at hand – defending his championship belts against Mthalane.

Donaire said that he’s been preparing well for Mthalane, a dangerous fighter that is virtual unknown by many casual boxing fans.

“He’s a tough guy,” said Donaire about Mthlane. “I call him a wild dog because he can run all day, punch all day, he’s always in shape when he gets into that ring you know so I want to get to that level in terms of stamina. I know have the upper hand when it comes to speed and power so we want to work really hard and not take this guy lightly.”

“Like me before nobody heard of me,” added Donaire. “And I took out the biggest guy out there [Darchinyan] and now I’m the top guy and that’s why I’m not taking anything lightly.”

Top Rank President Bob Arum said that the fight’s not going to be easy for Donaire but he expects Donaire to win.

“It’s the reason why we signed him,” said Arum about Donaire. “We believe that he can be the next Manny Pacquiao.”

With the fight coming close to the mega showdown between Pacquiao and Oscar De La Hoya, tickets for Donaire’s fight is reasonably priced, said Arum

“We understand what’s going on with the economy these days and we want to put out a fight that’s affordable for everybody,” said Arum.